I'd like to create a plane mesh which is divided to arbitrary-form polygon regions, like gimp/Photoshop mosaic filter makes, or like Voronoi diagram (although the latter is not really arbitrary). So I want each piece of that mosaic plane to be a single face, and it also would be great to assign a (random) height to each face, making a stair-step terrain from the plane. What I've tried so far:
1) To generate a Voronoi diagram, paint each region in a grayscale value, and try to use it as a heightmap (import image as plane, then Displace with image texture). That was useless in terms of mosaic-faced plane fragmentation, of course, but I hoped that each diagram region will get its own height based on the color, so I'll get my stair-step terrain. That failed, it seems Displace doesn't work that way - it made a soft and smooth terrain, instead of sharp step-like breaks.
2) To take a mosaic picture as a texture, and use the Knife tool to draw the actual mosaic polygons over it. It works that way, but requires a lot of work by hand.
3) To open a Python console and try to make a Voronoi diagram right in Blender. Then I realized that what my code does is painting each pixel into corresponding region's color, so it doesn't create any edges or faces at all. Maybe there's some other algorithm (I don't actually need Voronoi diagram; anything that looks like about the same is ok) which will allow me to end up with a set of faces?